Tgrendl,
I like your way of illustrating the issue, so let me try again:
If while hovering at 100% rpm at torque of 80%, your tail rotor becomes stuck at a fixed pitch setting. If you creep the rpm down to 95%, while holding hover height, the torque will rise to about 84% (1.05 x 80), because the power is a constant, and power is torque times rpm (84 torque times 95 rpm = 80 torque times 100 rpm).
Because the torque is now higher (and the tail rotor has less rpm for the stuck pitch position), the tail rotor thrust is insufficient, so the aircraft will rotate to the right.
In the same circumstance, if the pilot sneaks the rpm up to 105% and holds altitude with reduced collective pitch, the torque will go down to about 75%, and the tail rotor will now be producing excess anti-torque, so the aircraft will rotate to the left.
In other words, the rpm can be used as a yaw control if well handled!
The effects are used in the Huey stuck pedal procedure we have all practiced at one time or another, mostly because the bicycle chain tail rotor control on a Huey was more prone to failure at one time. I do not believe this is true any longer, but I defer to those who have more knowledge.
One comment on all this stuff - we tend to focus on the emergencies that we can practice, so I have seen people do 5 of these stuck pedal procedures in one flight, and 5 or ten engine failures for the remainder. If one studies accident statistics, CFIT and the like are more likely to bite us. Why don't we practice not hitting the ground!